The present invention relates in general to draft gear assemblies for cushioning shocks in railway rolling stock and, more particularly, to a lighter weight draft gear assembly which retains the same shock absorbing capacity.
Draft gear assemblies in use prior to the present invention are taught in U.S. Pat. Nos. 2,916,163; 3,178,036 and 3,447,693 and are owned by the assignee of the present invention. The above identified patents are all incorporated herein by reference.
In order to reduce the weight of railroad cars, it is desirable to keep the weight of auxiliary equipment low on such cars at a minimum. The draft gear in the prior art reference patents all weighed about 386 pounds or more. There are two reasons why lighter weight draft gears are desirable. First, less energy is required to move the railroad car and secondly more payload can be carried by such car for the same amount of energy.
However, even though it has been known that a lighter weight draft gear was desirable for these reasons, such draft gear must maintain minimum shock absorbing capacity as specified by the Association of American Railroads (A.A.R.) standards. For example, these gears have a specified capacity of at least 36,000 foot pounds. It is also important to note that the action of the friction system permits this to be accomplished without exceeding a 500,000 pound reaction pressure on the car sills in order for these high energy shocks to be readily handled without upsetting the coupler shank.